Angelina Jolie apparently stuck to prisoner of war rations in solidarity with her cast when she was shooting Unbroken.

The actress’s war drama is partly set in a PoW camp in Japan, and some of the actors had to lose weight to make it look authentic.

Japanese pop star Miyavi, who plays a brutal camp sergeant, told RadioTimes.com that the Hollywood star cut back on food too in support of the cast.

A picture of Miyavi and Angelina Jolie at an Unbroken photocall
Miyavi revealed Angelina Jolie showed solidarity with the Unbroken cast (Rob Griffith/AP/Press Association Images)

“She came to the set every day, giving advice to the actors, and she actually didn’t eat much [either],” he said.

“She was so thin because most of the actors were not able to eat because they’re prisoners in the prison camp. So she was so close to us.”

The newcomer revealed Angelina – who was forced to miss the film’s premiere as she was suffering from chicken pox – motivated the rest of the cast through the tough shoot.

“I really respect her professionalism, her attitude towards the creation – she’s so determined and passionate,” said the newcomer. “It was intense on set but with her motivation and attitude we were on the same page.”

Unbroken tells the true story of Louis Zamperini, a Second World War hero and athlete who ran in the 1936 Berlin Olympics.

Zamperini, played by British actor Jack O’Connell, survived a harrowing 47 days afloat in the Pacific Ocean following the 1943 crash of his US military plane and spent the following two years as a prisoner of war after washing up behind Japanese lines.

A picture of Angelina Jolie and Jack O'Connell in Unbroken
Angelina Jolie directed Jack O’Connell in Unbroken (Universal Pictures)

As well as the dieting, Angelina also showed she wasn’t afraid to get her hands dirty by trying out the stunts required of former Skins star Jack.

“She did test out all of my stunts before I had to do them,” he said.

One involved supporting a heavy wooden plank above his head for hours.

“The plank – I’m not sure if that can be regarded as a stunt – but, in any case, she was under it before I turned up on set,” he said.

:: Unbroken is in cinemas on Friday, December 26.